Fluid-power-transmission pump or motor



C. R. PRATT.

FLUID POWER TRANSMISSION PUMP 0R MOTOR.

APPLICATION FILED FEB. 16, I920.

Patented D60. 14, 1920.

a SHEETS-SHEET 1.

i; INVENTOR. MiQQb; M w;

ATTORNEKS- 0.- R. PRATT. FLUID POWER TRANSMISSION PUMP 0R MOTOR.

. A P P L l C A T l O N F L E D F [8- I6, I920. 1,362,040. 7 Patented Dec. 14, 1920.

v 3 EEEEEEEEEEEE 2- A TTOR/VEKS' C. R. PRATT.

FLUID POWER IRANSMISSIONPUMP 0R MOTOR. APPLICATION FILED FEB. 16, 1920.

1,362,040. Patented Dec. 14, 1920.

3 SHEETSSHEET 3- INVENTORI v WMQMJQ 01 QWAY (3% A TTORNEYS [UNITED STATES PATENT OFFICE.

CHARLES R. PRATT, OF MONTCLAIR, NEW JERSEY, ASSIGNOB TO UNIVERSAL SPEED CONTROL COMPANY; A CORPORATION OF NEW YORK. l

' FLUID-POWER TRANSMISSION PUMP 0R MOTOR.

Specification of Letters Patent.

Patented Dec. 14, 1920.

Application filed February 16, 1920. Serial No. 359,111. 1

To all wliomit may concern: 7

Be it known that I, .UHARLES citizen of the United States, of Montclair, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Fluid-Power- 'lransmission Pumps or Motors, of which the following is aspecification.

This invention relates to rotary pumps or motors in which an annular series of pistons mounted in the cylinders of a rotary barrel are connected to a power or drive shaft by means adapted to cause said pistons to move in an elliptical path, whereby rotation of said shaft will cause the pistons to reciprocate and pump a fluid or the admission of a fluid under pressure to said cylinders will cause thepistons to rotate said shaft to which they are connected. A pump or motor of this general character is shown in my prior Patents, No.1,137283 of April 27, 1915, No. 1,156,133 of October 12, 1015, and No. 1,163,849 of December 14, 1915.

The objects of the present invention are to provide means whereby the vibration or chattering of the mechanism, due to the continually changing registry of the various cylinders with the inlet and outlet passages of the device and the successive entry of the various cylinders into com1nunication with each of said passages, is taken up or absorbed by the fluid pressure itself; to thus provide means for relieving the casing or bearings of the device of such jars or vibrations and reducing the noise and violence of said jars or vibrations incident to operation of the device; to provide novel means for the utilization of the fluid pressure to maintain the cylinder barrel against its seat and reduce leakage, thus relieving R. PRATT, a and a resident the necessity for reducing the ports of said cylinders and causing throttling or'retarding of the passage of fluid to and from said cylinders; to secure means for transmitting such thrusts through the cylinder barrel shaft against the same fluid pressure which is delivered by or to the pistons; to provide the shaft with a balance piston for said purposes. and to, secure means for keeping such piston chamber always in communication .with the pressure side of the device: to provide initial spring pressure for seating the cylinder barrel; to retard leakage from the balance piston chamber; to provide with a tilting disk mounted on. a spherical bearing nication with the inlet on the cylinder shaft tilting means free from said dlsk radially; to enable the leakage from the balance piston chamber to lubricate said spherical bearing, and to obtain other advantages and results as! may be brought out in the following description.

Referring to the accompanying drawings, in which like numerals of reference indicate the same parts throughout the several views,

Figure l is a vertical longitudinal sectional View through a pump or motor 'em-. bodying my invention, on the line 11 of Fig. 2;

Fig. 2 is a transverse on the line 22 of Fig.

1, and

y Fig. 3 is a similar view taken on the line 3-3 of Fig. 1, the power transmis ion disk and its carrier ring being shown in front elevation.

In the specific embodiment of the invention illustrated by the drawings, the numeral l designates a pump or motor casing provided with a removable head 2 fastened thereon as by the screws 3. Disposed axially of said casing 1 and extending substantially the full length thereof is a shaft 4, said shaft being journaled ing 5 at the inner end of the casing and in the head 2 thereof, said shaft extending through a stuffing box 6 out of the casing and serving 'as a drive shaft for the machine when the same is running as a pump and as a power shaft when running as a motor.

A cylinder barrel 7 is fitted over said shaft and mountedto rotate therewith in any suitable manner, as by the key 8, said cylinder barrel being. provided with an annular series of longitudinally extending cylinders 9 axially parallel with the said shaft 4. Each of said cylinders 9 is provided with a port 10 which during rotation of the barrel registers successively with the inlet and outlet ports 11 and 12, respectively, of

casing head 2 and against which the ported end of the cylinder barrel fits in the manner of a valve. The said ports 11 and 12 of the seat plate 13 are arranged in commuand outlet passages 14 and '15 of'the machine which are disposed in the casing head 2. Y

Mounted Within the cylinders 9 are pistons 16 which are connected by piston rods sectional view taken in a ball beara seat plate 13 secured to the inside of the drive plate pistons '16,

1'? tea power transmission disk 18, the ex-- tremities of said piston rods having spherical ends 19 which fit within corresponding sockets 20 in the disk 18. This power trans- 25 is slidably loose on the shaft 4 and a spacing sleeve 40 on said shaft between. it and the, ball bearing 5 on the casing for the shaft enables adjustment of the spherical bearing longitudinally of the shaft to be made nuts 41, 42 at the end of the shaft. Only slight adjustment is necessary, so as to take up wearbetween the disk-18 and its tilting rmg and any other suitable means can be employed. 1

The transmission disk 18 is positively "driven by the pistons to rotate with thecylinder barrel 7 by means of a drive plate 26 substantially the same in construction and 'o eration as the drive plate disclosed in myatent No. 1,137,283, above-mentioned, said being fastened upon the end of the cylinder barrel 7 and provided with notchesor slots 27 to receive the'respective piston rods 1. For tilting the transmission disk 18, I have shown a ring 22 at the side of the disk next the cylinder barrel, free from said disk radially and engaging the same only in a direction perpendicular to the planes of said disk and ring, as by an an nular anti-friction bearing 21* between the disk and ring. The tiltingring 22 is journaled upon trunnions 23 in the casing 1, and is adapted to be tilted by any suitable means such .as a handle lever 24 upon one of said trunnions 23 exteriorly ofthecasing 1.

In the operation ofthe device as a pump, it will be obvious that upon power being ap-. plied to the shaft 4 from'a suitable source, the cylinder barrel and transmission disk will be rotated to cause reciprocation of the and that the rotation-of the cylinder barrel 7 will cause successive registry of'the cylinders with the inlet and exhaust passages 14 and 15. The cylinders as they under pressure through register with the inlet passage will be filled. with fluid by the reciprocation. of thepistons outwardly of the cylinders, while as the cylinders register with the outlet passage 15, the pistons will be reciprocating in the opposite direction to force or pump the fluid the outlet passage 15.' On the other hand, whenfluid under pressure is admitted to the inlet passage 14 and cylinders, the pistons will operate as motors to drive i the fluid taking'place through the outlet .passage 15. Obviously if the transmission disk 20 isswung at an angle opp the shaft 4, the exhaust ofe to that shown in Fig. 1 the'direction of rotation of the shaft 4 will be'reversed, and the inlet passage 14and outlet passage 15'then become the outlet and-inlet, respectively. It will be noted that during rotation of the cyl-' inder barrel, first three and then four cylinders will be in registry with the inlet and outlet passages 14 and 15; that is, at certain points'in the rotation of the cylinder barrel there will be only three cylinders in registry with either the inlet or the voutlet'passage, as shown by Fig. 2, and as one of these cylinders is about to pass out of registry with the passage another or fourth cylinder will be just coming into registry with said passage. This change in the number of cylinders in communication with" the inlet and outlet passages, and also the constant entering and leaving of the various cylinders into and from communication with the inlet and outlet passages, causes a vibration of the 'mechanism which if the transmission disk were mounted directly upon the casing 1 would produce a chattering noise and disturbance, as well as injury to and undue wear upon the mechanism.

One step toward the elimination of these I difficulties is the mounting of transmission chamber is in communication with the inlet and outlet passages 14'and 15 through the duct 30 which communicates with the duct 31 communicating with each of said passages. A ball valve 32 is-"a'rranged in said duct 31 at each end thereof, so that only fluid under pressure is admitted to the piston chamber 28 at any time, thesaid ball valves allowingfor a reversal of the'inlet and outlet passages due to changes in direction of rotation of the cylinder barrel. It will thus be seen that the longitudinal thrusts and vibrations of the pistons upon the transmission disk 18 will be transmitted through the spherical bearing 25 to the shaft 4', and the fluid in the piston chamber 28 acting upon the piston 29 will effectively absorb them. It will also be noted that the fluid pressure 'actingon the balance piston 29 being the same as that produced in or driving the machine, the shocks and jars cannot be greater thanthis pressure and thus may-be thor- 'oughly absorbed by'the fluid pressure. Fur-c thermore, the radial thrusts of the piston rods. onthe transmission disk are transmit ted to the shaft 4 by the spherical bearing 25. The function of tilting ring 22 and roller thrust, bearing 21 is first to vary the angle of transmission disk 18 to the axis of shaft 4 1n the direction which controls the stroke of the pump, and this angular motion is not 0p-- pressure of one piston to the thrust roller diametrically opposite to the pressure pistons. This is the only pressure transmitted to the casing 1, and because it is only about onequarter of the total piston pressure, andalso because it is not caused by pistons entering and leavingthe pressure chamber, it produces little if any vibration in casing 1.

As is well known in the art relating to pumps of this general type, vibrations originate at the points of intake and cut off, and means to eliminate the same have been tried with only partial success by special forms of ports, relief grooves, and so forth. I By my invention, these vibrations are caused to react directly on the pressure which caused them, as for example in the pump shown in Fig. 1, the lower and outer piston has just entered the pressure port and gives a sudden thrust against disk 18; this is first transmitted to spherical bearing 25, shaft 4 and piston 29, and then to the diametrically opposite piston. lVe therefore have these three pistons, 16, 16 and 29, reacting against the same pressure fluid, and transmitting the vibrations in tension through the axis of shaft 4 and in compression through rods 17, thereby eliminating the objectionable metallic vibrations and noise when such vibra-' tions are transmitted to the casing through a roller thrust bearing and a tilting ring as has been done heretofore.

It is also a feature of my invention to utilize the fluid pressure upon the balance piston 29 to seat the'cylinder barrel 7, either entirely or partly, and this I have shown accomplished by having the cylinder barrel held against movement away from its seat on the shaft 4, as by a shoulder 13 on the shaft engaging the end of the barrel away from its seat. Then by having the effective area'of the piston 29 'greater than the sum of the areas of the cylinder ports 10,- the pressure on the fluid acting on said piston will maintain the cylinder barrel seated against the plate, 13 as closely as desired. To seat the cylinder barrel when there is no pressure in the piston chamber 28, a spring 35 is interposed between the piston der barrel, the tendency and the end of said chamber next the cylinof saidsprin being td hold the cylinder barrel against t e seat p ate.

To lessen leakage of the pressure fluid from the piston chamber 28, a bearing bushing 33 is fitted in the casing head 2, and the shaft 4 passing through this bushing is formed with a helical groove 34 the convolutions ofwhich are such that any fluid around the shaft tends to be forced back into the phamber 28, said groove also distributing the fluid as a lubricant over the bearing'in the bushing 33. Similarly, to prevent the 'pressure fluid from escaping from the chamber 28 around the piston 29 the piston is provided with a peripheral helical groove 36, which groove .tends to force the fluid back into the chamber 28 and thoroughly distributes it as a lubricant over the piston. Fluidwhich actually escapes through the helical grooves 34 and 36 passes through transverse ducts 37, 37 ,in the shaft' l into a ;.duct 38 extending longitudinally of the shaft and so by other'radial ducts 39 at the spherical bearing 25 to lubricate the joint'lbetween said spherical bearing and the transmission disk 18 before entering the casing.

Obviously, detail modifications and changes may be made in manufacturing my invention by those skilledin the art without departing from the spirit and scope of the invention, and I do not wish to be understood as restricting myself except as required by the'following claims when con- .strued in the light of the prior art.

Having thus described the invention, what claim is: 1. In a device of the character described, a shaft,.a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, means for causing said pistons to move in an elliptical path, and means for transmitting to said shaft thrust of said pistons longitudinally of the shaft.

2. In a device ofthe character described, a casing, a shaft normally held against longitudinal -movement with respect to said casing, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, means for causing said pistons to move in an elliptical path, and means for transmitting to said shaft thrust of said of the shaft.

3. In a device of the character described, a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders,-pistons in said cylinders, means for causing said pistons to move in an elliptical path, and means for transmitting to said pistons longitudinally shaft thrust of said pistons both longitudinally'of the shaft and radially of the disk. 4. In a device of the. character described, a shaft, a cylinder barrel mourited on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, means for causing said pistons to move in an elliptical pa'thyand meansfor transmitting to said shaft all thrust of the pistons other than that which transmits power through the device.

5. In a device of the characterdescribed, a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, a spherical bearing on said shaft, means normally preventing movement of said spherical bearing longitudinally of the shaft, a transmission disk for said pistons mounted upon said spherical bearing, means for causing said disk to turn 'with the cylinder barrel, and means for tilting said disk.

6. In a device of the character described, a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, a spherical bearing on said-shaft, means holding said spherical bearing against movement away .from the barrel longitudinally of said shaft,

a transmission disk for said pistons mounted upon said spherical bearing, means for causing said disk to turn with the cylinder barrel, and means for tilting said disk.

7. In a device of the character described, a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylin-' ders, pistons in said cylinders, a spherical bearing on said. shaft, meansadjustably holding said spherical bearing against movement away from the barrel longitudinally ofsaid shaft, a transmission disk for said -pistons mounted upon said spherical bearing, means for causing said disk to turn with the cylinder barrel, and means for tilting said d1sk.

I 8. In a device of the character described, a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylinders, pistons in said cylinders, a spherical bearing on said shaft, means holding said spherical bearing against movement away I from the barrel longitudinally of said shaft,

a transmission disk for said pistons mounted upon said spherical bearing, means for causing said diskto turn with the cylinder barrel, and a tilting ring for said disk free from the same radially. v

9. In a device of the character described,

'a shaft, a cylinder barrel mounted on said shaft to turn therewith, fluid inlet and outlet means communicating with the cylin ders, pistons in said cylinders, a spherical bearing on said shaft, means holding said spherical bearing against movement away from the barrel longitudinally of said shaft, a transmission disk for said pistons mounted upon said spherical bearing, means for causing said disk to turn withthe cylinder barrel, and a tilting ring for said disk at the side of the same next.the cylinder barrel..

10. In a device of the character described, a casmg having a head providing fluid inlet and outlet passages and a seat plate and a piston chamber communicating with said passages, a shaft having a piston in said piston chamber, a cylinder barrel on said shaft held against movement thereon away from its scat, means keeping said piston means for exerting force upon said shaft to seat the cylinder barrel.

12. In a device of the character described, a cas ng, a shaft in said casing, a cylinder barrel on said shaft held against movement thereon away from its seat, and means for exerting fluid pressure on said shaft 'to seat the cylinder barrel.

13.- In a device'of the character described,

a casing, a shaft in said casing, a cylinder barrel on said shaft held against movement thereon away from its seat, and means for causing the fluid passing under pressure through the device to act on said shaft to seat the cylinder barrel.

14."In a device of the character described, a casing, a shaft in said casing, a-cylinder barrel on said shaft held against movement thereon away from itsseat, a spring'acting on said shaft to seat the cylinder barrel, and

means for causing the fluid passing under pressure throfigh the device to act'on said shaft to seatthe cylinder barrel.

- 15. In a device of the character'des cribed, a casing having a head providing a seat, a

shaft extending through said head, a cylinder barrel on said shaft and seat and held against'movement on the shaft away from the seat, a piston on the shaft at the opposite side of the seat'ffromthe barrel, and meansv for causing the fluid passing under pressure through the device to act on said piston to seat the cylinder barrel.

16. In a deviceof the character described,

a casing having a head providing a seat, a

shaft extending through said head, a cylinder barrel on said shaft and seat and held against movement on the shaft away from the seat, a piston on the shaft at the opposite side of the seat from the barrel, a spring acting to seat the cylinder barrel, and means for causing fluld passing under pressure through the device to act on said piston to seat the barrel.

17. In a device of the character described, a casing having a head providing a seat, a shaft extending through said head, a cylinder barrel on said shaft and seat and held against movement on the shaftaway from the seat, a piston on the shaft at the opposite side of the seat from thebarrel, and

means for causing fluid passing under pressure through the device to act on said piston to seat the cylinder barrel, said piston having peripheral helical grooves tending to force leakage back to the pressure side of the piston.

18. In a device of the character described, a casing having a head providing a seat, a shaft extending through said head, a cylin der barrel on said shaft and seat and held against movement on the shaft away from the seat, a piston on the shaft'at the opposite side of the seat from the barrel, and means for causing fluid passing under pressure through the device to act on said piston to seat the cylinder barrel, said-shaft where it passes through the head havingper'ipheral helical grooves tending to force leakage back toward the piston.

19. In a device of the character described, the combination with an annular series of pistons and means for causing them to move in an elliptical path, of fluid pressure means for opposing the longitudinal thrust of said pistons.

20. In a device of the character described,

the combination with an annular series of pistons and means for causing them to move in an elliptical path, of fluid pressure means for balancing the longitudinal thrust of said pistons.

21. In a device of the character described,

- the combination with an annular series of opposing the longitudinal thrust of said pis-' tons on said shaft.

23. In a device of the character described. the combination with an annular series of pistons and means for causing them to move in an elliptical path, of means for utilizing the pressure of fluid passing through the deviceto oppose the longitudinalv thrust of said pistons.

24. In a device of the character described. the combination with an annular series of pistons and a disk for causing them to move in an elliptical path, of a fluid chamber in communication with the pressure side of the device, and means for transmitting longitudinal thrust of the pistons on said disk to the fluid in said chamber.

25. In a device of the character described,

the combination of a shaft, an annular series of pistons aroundsaid shaft longitudinally thereof, means for transmitting to said shaft longitudinal thrust of said pistons, and means for transmitting to said shaft, in opposition to' said thrust, pressure from the fluid passing through the device.

26. In a device of the character described.

cylinder barrel, pistons in the cylinders, a

disk for causing said pistons to move in an elliptical path, and fluid pressure means opposing longitudinal thrust of said piston on said disk and seating the cylinder barrel.

27 In a device of the character described. a cylinder barrel, pistons in the cylinders, a disk for causing said pistons to'move in an elliptical path, and means for utilizing the pressure of fluid passing through the device said .disk and seat the cylinder barrel.

29. In a device of the character described, a casing having a head providing a seat, a shaft extending through said head, a cylinder barrel on said shaft and'seatand held against movement on the shaft away from the seat, pistons. in the cylinders connected to said shaft to move in an elliptical path, a piston on the shaft, and means for causing fluid passing under pressure through the device to act on said piston in opposition to the longitudinal thrust of the cylinder pistons.

30. In a device of the character described, a casing having a head providing a seat, a

shaft extending throughsaid head, a cylinder barrel on said shaft and seat and held against movement on the shaft away from the seat, pistons in the.- cylinders connected to said shaft to move in an elliptical path,

a piston on the shaft at the opposite side of the seat from the cylinder barrel, and means for causing fluid passing under pressure through the device to act on said DlStOIlin opposition to the longitudinal thrust of the cylinder piston.

31. In a device of the character descrlbed, a casing having a head providing a seat, a

shaft extending through said head, a cylinder barrel on said shaft and seat and held against movement on the shaft away from the seat, pistons in the cylinders connected to said shaft to move in an elliptical path, a

, piston'on the shaft, and means for causing der barrel on said shaft and seat and held against movement on the shaft away from the seat, pistons in the cylinders connected to said shaft to move in an elliptical path,

a piston on the shaft at the opposite side of the seat from the cylinder barrel, and means for causing fluid passing under pressure through the device to act on said piston to seat the cylinder barrel and oppose the longitudinal thrust of the cylinder pistons on the shaft.

33. In a device of the character. described,

' a casing having a head providing a seat, a

shaft extending through said head, a cylinder barrel on said shaft and seat and held.

against movement on the shaft away from the seat, pistons in the cylinders connected to said shaft to move in an elliptical path, a piston on the shaft at the opposite sideof the seat from the cylinder barrel, means for causing fluid passing under pressure throu h f the device to act on said piston to seatt e cylinder barrel. and oppose the longitudinal thrust of the cylinder pistons on the shaft, and spring means for seating said cylinder barrel when the device is idle. a

34. In a device of the character described,

a casing having a head providing a seat, "a shaft extending through said head, a cylinder barrel on said shaft and seat and held against movement on the shaft away from the seat, pistons in the cylinders connected to said shaft to move in an elliptical path,

a piston on the shaft, andmeans for causing fluid passing under pressure through the device to act on said piston in opposition to the seat, pistons in the cylinders connected to said shaft to move in an elliptical path,

a piston on the shaft at the oppositeside of. the-seat from the cylinder barrel, and means for causing fluid passing under pressure throu h the device to act on said piston inopposltion to the longitudinal thrust of thecylinder pistons, said shaft where it passes through the head having peripheral helical grooves tending to force leakage back toward the piston.

36. In a device of the character described,

a shaft, an annular series of pistons disposed longitudinally of said shaft, a spherical,

bearing on said shaft, a disk on said bearing for causing the pistons to move in an elliptical path, a piston on the shaft, me'ans'for exerting fluid pressure on said iston in opposition to the longitudinal t rust of the other pistons, and means for conducting leakage from the shaft piston chamber to said s herical bearing to lubricate the same.

.37. n a device of the character described, a shaft, an annular series of istons disposed longitudinally of said shaf cal bearing on. said shaft, a disk on said bearing for causing the pistons to move 'in 1 an elliptical path, a piston. on the shaft,

means for exerting fluid pressure on said piston in opposition to the longitudinal thrust of the other pistons, and ducts in the shaft and spherical bearing for receiving leakage from the shaft piston chamber for lubrication purposes.

, CHARLES R; PRATT.

t, 'a spheri- 

